Create filesystem with given features (filesystem options), overriding
the default filesystem options. The default features which are
enabled by default are specified by the
base_features
relation, either in the
[libdefaults]
section in the
/etc/mke2fs.conf
configuration file,
or in the subsection of the
[fs_types]
section for the usage types as specified by the
-T
option, further modified by the
features
relation found in the
[fs_types] section
based on the filesystem and usage types. See the
mke2fs.conf(5)
manual page for more details.
The filesystem type-specific configuration setting found in the
[fs_types]
section will override the global default found in
[libdefaults].
The filesystem feature set will be further edited
using either the feature set specification specified by this option,
or if this option is not specified, by the
default_features
relation for the filesystem type being created, or in the
[libdefaults]
section of the configuration file.
The filesystem feature set is comprised of a list of features, separated
by commas, that are to be enabled. To disable a feature, simply
prefix the feature name with a caret ('^') character. The
pseudo-filesystem feature "none" will clear all filesystem features.
-
- large_file
-
Filesystem can contain files that are greater than 2GB. (Modern kernels
set this feature automatically when a file > 2GB is created.)
- dir_index
-
Use hashed b-trees to speed up lookups in large directories.
- filetype
-
Store file type information in directory entries.
- flex_bg
-
Allow bitmaps and inode tables for a block group to be placed anywhere
on the storage media (use with -G option to group meta-data in order
to create a large virtual block group).
- has_journal
-
Create an ext3 journal (as if using the
-j
option).
- journal_dev
-
Create an external ext3 journal on the given device
instead of a regular ext2 filesystem.
Note that
external-journal
must be created with the same
block size as the filesystems that will be using it.
- extent
-
Instead of using the indirect block scheme for storing the location of
data blocks in an inode, use extents instead. This is a much more
efficient encoding which speeds up filesystem access, especially for
large files.
- uninit_bg
-
Create a filesystem without initializing all of the block groups. This
feature also enables checksums and highest-inode-used statistics in each
blockgroup. This feature can
speed up filesystem creation time noticably (if lazy_itable_init is
enabled), and can also reduce
e2fscktime
dramatically. It is only supported by the ext4 filesystem in
recent Linux kernels.
- resize_inode
-
Reserve space so the block group descriptor table may grow in the future.
Useful for online resizing using
resize2fs.
By default
mke2fs
will attempt to reserve enough space so that the
filesystem may grow to 1024 times its initial size. This can be changed
using
resize
extended option.
- sparse_super
-
Create a filesystem with fewer superblock backup copies
(saves space on large filesystems).